/* 深色主题配色方案 - 参考传统深色系方案[8](@ref) */
:root {
    --bg-dark: #0f172a;        /* 主背景色 */
    --card-bg: rgba(30, 41, 59, 0.8);        /* 卡片背景 */
    --accent: #3498db;          /* 强调色（按钮/交互） */
    --text-primary: #f0f0f0;    /* 主文字 */
    --text-secondary: #b0b0b0;  /* 辅助文字 */
    --border-color: #444;       /* 边框色 */
    --success: #2ecc71;         /* 成功提示 */
    --error: #e74c3c;           /* 错误提示 */
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 20px;
    position: relative;
}

/* 顶部返回按钮 */
.back-button {
    position: absolute;
    top: 20px;
    left: 20px;
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 8px 15px;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s;
}

.back-button:hover {
    background-color: rgba(255,255,255,0.1);
    border-color: var(--accent);
}

/* 主内容容器 */
.container {
    max-width: 1200px;
    margin: 60px auto 80px;
    display: flex;
    gap: 30px;
    justify-content: center;
    align-items: center;
}

/* 左侧用户信息面板 */
.user-panel {
    flex: 1;
    background-color: var(--card-bg);
    border-radius: 8px;
    padding: 30px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
    display: flex;
    flex-direction: column;
    align-items: center;
}

.avatar-container {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    overflow: hidden;
    border: 3px solid var(--border-color);
    margin-bottom: 25px;
}

.avatar {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.username {
    font-size: 1.8rem;
    margin-bottom: 40px;
    font-weight: 500;
}

/* 模式选择器 */
.mode-selector {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.mode-btn {
    background-color: rgba(255,255,255,0.08);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 12px;
    border-radius: 6px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
}

.mode-btn.active, .mode-btn:hover {
    background-color: var(--accent);
    border-color: var(--accent);
}

/* 右侧表单区域 */
.form-panel {
    flex: 1;
    background-color: var(--card-bg);
    border-radius: 8px;
    padding: 30px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.form-title {
    font-size: 1.5rem;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border-color);
}

/* 头像管理表单 */
.avatar-form {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.avatar-preview {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    overflow: hidden;
    margin-bottom: 25px;
    border: 2px solid var(--border-color);
}

.avatar-preview img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.file-input {
    display: none;
}

.file-label {
    background-color: var(--accent);
    color: white;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    margin-bottom: 15px;
    transition: background-color 0.3s;
}

.file-label:hover {
    background-color: #2980b9;
}

/* 信息管理表单 */
.info-form {
    display: flex;
    flex-direction: column;
}

.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-secondary);
}

.form-input {
    width: 100%;
    padding: 12px;
    background-color: rgba(0,0,0,0.2);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--text-primary);
    font-size: 1rem;
}

.form-input:focus {
    outline: none;
    border-color: var(--accent);
}

.submit-btn {
    background-color: var(--accent);
    color: white;
    border: none;
    padding: 12px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    margin-top: 10px;
    transition: background-color 0.3s;
}

.submit-btn:hover {
    background-color: #2980b9;
}

/* 底部版权信息 */
.footer {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    text-align: center;
    padding: 15px;
    background-color: rgba(0,0,0,0.5);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        flex-direction: column;
        margin-top: 40px;
    }

    .back-button {
        top: 10px;
        left: 10px;
    }
}